1. Field of Invention
The present invention relates to a method for recycling rubber scrap, primarily scrap tire carcasses reduced to particles of various sizes and geometrical configurations, tire tread buffings, ground rubber dust, synthetic or textile fibers used in the production of rubber products, or other scrap rubber; to obtain final recycled rubber products of various defined thicknesses, widths, and lengths. The method is characterized by its use of ingredients which are intimately mixed, formed in a mold and submitted to pressure, steam, and cooled; or by production on an automated assembly line where scrap rubber particles, with or without synthetic or textile material, are fed by a apparatus system for the continuous production of scrap rubber products. Products formulated according to this invention are suitable for a variety of uses as elements in building construction such as a subfloor construction material, exterior or interior wall construction material, ceiling construction material, subroof construction material, etc.; and display favorable thermal and acoustical insulation properties.
2. Background of the Invention
D. W. Huke states that most reclaimed rubber is obtained from tires, and that this rubber is treated so that it can be re-milled and incorporated into a rubber mix. D. W. Huke, INTRODUCTION TO NATURAL AND SYNTHETIC RUBBERS at 77 (1961). Virtually all the prior art literature concerning reclaiming rubber and methods for reclaiming concern themselves with obtaining a "de-vulcanized" product for use as a filler, additive, or extender in subsequent manufacturing operations. Testimony during the U.S. House of Representatives Committee on Small Business hearings on H. R. 4147. The Tire Recycling Incentives Act, emphasized that about 279 million used rubber tires are venerated in the United States annually. About 2.5 to 3 billion used tires litter landscapes and landfills across the United States. Most recycled scrap rubber tire material is manufactured into tires, recreational surfaces such as running tracks and tennis courts, and added to asphalt used for road pavement and other road products.
A method for recycling rubber scrap with foreign material such as textile fibers or metal removed, and rubber scrap ground to a substantially uniform size of a dry, sand-like consistency to yield final products such as highway guard rail extensions, railroad tie pads, paving "stones", and floor coverings of at least about one inch in thickness is disclosed in U.S. Pat. No. 4,244,841 to Frankland. U.S. Pat. No. 4,851,500 to Lalwani et al describes a process for making roofing products such as rolled roofing, tiles, shakes, slates, and walkway pads.
A method for forming foamed thermal insulating material from scrap rubber is disclosed in U.S. Pat. No. 4,174,308 to DiSanto. U.S. Pat. No. 4,039,645 to Clovis discloses a process for the manufacture of fire retardant particle board composed of wood particles.
Numerous methods and processes for fiber board and particle board are known in the prior art. U.S. Pat. No. 4,127,636 to Flanders discloses a process for making a reinforced board from lignocellulosic particles in which comminuted lignocellulosic particles, binders and other additives and additionally a plurality of elongate reinforcing filaments comprising a plurality of short filaments such as glass fibers or steel wires are distributed uniformly throughout the particle and binder mixture in a random orientation so as to extend generally in all directions. The lignocellulosic particles utilized are woody particles such as sawdust, bark, etc. but the resultant product can also employ any fibrous lignocellulosic material including various grain and vegetable products such as corn stocks. U.S. Pat. No. 3,916,059 to Molloy et al discloses crossbanding sheets which are made of a combination of glass fibers and cellulose fibers held together by a synthetic resin binder extending throughout the sheet, the fibers of the crossbanding sheets are oriented in a direction perpendicular to the direction of orientation of wood chips or grain of wood core. The sheets comprise a combination of glass fibers and cellulose fibers. U.S. Pat. No. 3,880,975 to Lundmark discloses a thin, continuous web produced from a starting material containing at least a major part of defibrated lignocellulose plant substance and a mixture of resinous binding agents. In addition to lignocellulose fibers and resin binders, the starting material may include mineral fibers including asbestos, glass and rockwool fibers; animal textile fibers, and vegetable textile fibers. Fibers were impregnated with amounts of moisture repellants, fire retarders, fungicides, insect repellants, etc. U.S. Pat. No. 4,110,397 to Wooler discloses an improvement in the molding process for composite bodies of sheets, especially those from lignocellulosic material in which an isocyanate binding agent is used. That patent defines lignocellulosic material as wood chips, wood fibers, straw, dried brushes, reeds, and grasses and may further include ground nuts and hulls from cereal crops. U.S. Pat. No. 4,565,662 to Mansson et al discloses a method for the production of particle boards by addition of a hydrophobing agent and a curable glue to wood based particles, shaping of the particle mass and subsequent curing of the glue by application of pressure and heat.
It is therefore apparent that there is a great need in the art for a method of manufacturing particle board of reclaimed or recycled rubber as taught in the prior art. Furthermore, it is also desirable that any such method would be sufficiently variable so as to provide building product materials having favorable thermal and acoustical insulation properties; and that such building product materials be manufactured of varying sizes, shapes, thicknesses, and degrees of hardness; and such particle boards be manufactured from scrap rubber, with or without synthetic or textile fibers. That is the subject matter of this patent.